What is Carbon Dioxide (CO2)
Posted on 30 November 2010

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About This Website.

This website is an effort to bring and collect most possible information available regarding the CO2 measuring using the remote sensing. There is a lot of work has been done in this regard that explain the use of remote sensing in order to collect and monitor the CO2 data. This webpage contains the comprehensive and detail scholarly collations regarding the technique use in remote sensing to measure and capture the Co2 or green houses gasses in our atmosphere.
This is an ongoing project and update will be posted as soon as available in coming days.

What is carbon dioxide (CO2) and what are the sources?

Carbon dioxide is a colorless, odorless gas. It is produced both naturally and through human activities, such as burning gasoline, coal, oil, and wood. In the environment, people exhale CO2 which contributes to CO2 levels in the air.

What levels of CO2 are typical indoors?

The outdoor concentration of carbon dioxide can vary from 350-400 parts per million (ppm) or higher in areas with high traffic or industrial activity.

The level of CO2 indoors depends upon:

-the number of people present.

-how long an area has been occupied.

-the amount of outdoor fresh air entering the area.

-the size of the room or area.

-whether combustion by-products are contaminating the indoor air (e.g., idling vehicles near air intakes, leaky furnaces, tobacco smoke).

-the outdoor concentration.

Carbon dioxide concentrations indoors can vary from several hundred ppm to over 1000 ppm in areas with many occupants present for an extended period of time and where outdoor air ventilation is limited.

Why do we measure CO2?

Carbon dioxide is often measured in indoor environments to quickly but indirectly assess approximately how much outdoor air is entering a room in relation to the number of occupants. CO2 can be measured with relatively inexpensive real-time digital air monitoring equipment. CO2 measurements have become a commonly used as a screening test of indoor air quality because levels can be used to evaluate the amount of ventilation and general comfort.

Outdoor "fresh" air ventilation is important because it can dilute contaminants that are produced in the indoor environment, such as odors released from people and contaminants released from the building, equipment, furnishings, and people's activities. Adequate ventilation can limit the build up of these contaminants. It is these other contaminants and not usually CO2 that may lead to indoor air quality problems, such as discomfort, odors "stuffiness" and possibly health symptoms.

The American Society of Heating, Refrigerating and Air-Conditioning Engineers (ASHRAE) has developed ventilation guidelines that should maintain a comfortable environment for most occupants. The amount of fresh air that should be supplied to a room depends on the type of facility and room. For example, in elementary school classrooms, ASHRAE recommends 15 cubic feet per minute person of outdoor air (for a 1000 square foot room occupied by 35 people). In office spaces, ASHRAE recommends 17 cubic feet per minute person (for a 1000 square foot occupied by 5 people). In addition, a Minnesota Department of Labor and Industry (MNDOLI) Rule states that "outside air shall be provided to all indoor workrooms at the rate of 15 cubic feet per minute per person (MN Rule, 5205.110)".

These rates of ventilation should keep carbon dioxide concentrations below 1000 ppm and create indoor air quality conditions that are acceptable to most individuals.

 

Measuring CO2 using Remote Sensing.

There are many conventional methods for quantification of sequestered carbon. Many of these methods are complicated, expensive and limited in their coverage. Such limitations impede sound quantification and monitoring of carbon. Remote sensing can provide answers against such measurement and monitoring limitations. The remote sensing approach can meet the requirements of carbon sequestration such as permanent sample plots (MacDicken, 1997) achieved by means of fixed coordinates, coupled with the systematic repetitive characteristic of most satellites. Tucker (1979), Richardson et al (1983), and Christensen and Goudriaan (1993) demonstrated that the reflection of the red, green and near-infrared (NIR)radiation contains considerable information about plant biomass.


 

The above story is presented by Environmental Health Minnesotaplease. Please contact the Indoor Air Unit at health.indoorair@state.mn.us, 651-201-4601 or 800-798-9050.